新型独立B型液化天然气船围护系统及蒸发率计算

Containment system of new independent type B LNG carrier and boil off rate calculation

以一艘17万立方米新型独立B型液化天然气(LNG)船为研究对象,将该型围护系统与传统薄膜型和MOSS独立球型围护系统进行详细对比,突出该型围护系统的特点;分析船体和舱室结构后,通过合理和必要的简化,提供了一种计算独立B型液货舱传热的方法,通过数值模拟计算不同工况条件下液货舱的蒸发率,研究了聚氨酯泡沫绝热材料的热导率变化对液货舱蒸发率的影响。得到以下结论:(1)新型独立B型围护系统与传统围护系统相比有突出优势,在将来有很好的应用前景;(2)绝热层厚度为450 mm时,为了满足日蒸发率不能超过0.1%的限定要求,所选用的绝热材料的热导率应当小于或等于0.03 W·m-1·K-1。

Based on the analyses of the containment system of a new independent type B liquefied natural gas(LNG)carrier with the total capacity of 17×104 m3,by comparing with the containment systems of traditional membrane-type and MOSS independent spherical type LNG carriers,the features of the new independent type B containment system are expressly highlighted.Based on the analyses of the hull and containment system structures of this LNG carrier,by taking into account of some reasonable and necessary simplification,a numerical simulation method is provided to calculate the heat transfer and the boil off rate of the containment system under different working conditions.And the effect of the thermal conductivity of reinforced polyurethane foam(RPUF)insulation material on boil off rate is studied.The following conclusions are obtained:(1) Given many advantages of the new independent type B containment system compared to traditional ones,this type of containment system has a promising application prospect in future.(2) When the thickness of insulation layer is 450 mm,the thermal conductivity of insulation material should be no larger than 0.03 W·m-1·K-1,in order to meet the requirement that the boil off rate is less than 0.1% per day.